What does a government have to gain by killing their population with a poorly made vaccine? Some corporation looking for a quick buck then maybe, but not a government. I think we have come a long way in creating safer medicines and vaccines.
Remember 10 years ago things like Small pox and measles were things that we didn't have worry about, people living in a time before electricity worried about those things. Now we are seeing diseases coming back and these use to be diseases that we took for granted as things we would never see again. I don't know about you, but I don't want to see black plague v2 spread because of ignorance.